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Table of Content

    18 October 2024, Volume 35 Issue 10
    Differences of driving factors for carbon sink changes in different carbon pools of Larix gmelinii natural forests
    MEI Xuesong, CHEN Guanmou, DONG Lingbo
    2024, 35(10):  2639-2647.  doi:10.13287/j.1001-9332.202410.006
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    Carbon balance of the tree layer in natural forests is affected by three carbon pools: tree growth, morta-lity, and recruitment. However, the dynamics of the sink of each carbon pool and the driving factors are still unclear. To this end, we used stepwise regression method and structural equation model to assess the effects of biotic (stand and diversity) and abiotic (soil, topography and climate) factors on three dynamic processes of carbon sinks, namely, stand growth, recruitment and mortality, in the natural forests of Larix gleminii, based on the data from the seventh and eighth national continuous forest inventory of the Greater Khingan Mountains. The results showed that the average growth, recruitment and mortality of L. gleminii stand were 0.73, 0.17 and 0.41 t·hm-2·a-1. The growth of carbon sink in forest stands increased with the slope aspect index (the total path coefficient β=0.135), stand basal area (β=0.132) and slope position (β=0.085), but decreased with the increases of average stand age (β=-0.225) and altitude (β=-0.196). Recruitment was negatively correlated with stand basal area (β=-0.368), average stand age (β=-0.240), soil pH (β=-0.184), soil total phosphorus (β=-0.115) and tree species richness (β=-0.012), and was positively correlated with soil total nitrogen (β=0.258). The larger important factors affecting mortality were the average tree height (β=0.276) > Simpson index (β=0.232) > soil total phosphorus (β=0.195) > stand basal area (β=0.154) > soil pH (β=0.084). Stand age, basal area and average tree height were the most important factors affecting stand carbon sink growth, recruitment and mortality. Topography and soil conditions were also the key to affect stand dynamics. Therefore, the structure and soil conditions of the forest can be adjusted through reasonable thinning in the management process, which in turn promotes the sustained fulfilment of forest carbon sink capacity.
    Relationship between the prophase growth of knots and the radial growth of trunk in Pinus koraiensis
    BAI Suriguga, JIA Weiwei, GUO Haotian
    2024, 35(10):  2648-2656.  doi:10.13287/j.1001-9332.202410.009
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    We analyzed the differences in knot property of linear and curved knots of dominant, medium, and inferior wood with thirty-three Pinus koraiensis trees from Mengjiagang Forest Farm and Linkou Forestry Bureau in Heilongjiang Province. We divided the 33 trees into two groups according to the height of the site index. We constructed a trunk diameter growth models to explore the connection, between the knot growth inflection points and the successive growth of diameter, and to screen for the types that had a weaker impact on wood quality. The results showed that there were significant differences in knot diameter, sound knot length, proportion of loose knot and inflection point age between the two knot types. The growth inflection point of curved knot was between 8 and 12 years old, while that of linear knot was between 7 and 10 years old. The knot of curved knots in different grades of wood were larger than linear knot in terms of knot diameter and sound knot length. The decrease in the proportion of sparse knots indicated that the healing time of knot became shorter. The growth of linear knots remained essentially uniform with radial growth. The age of the growth inflection point of curved knots was later than the age at which the maximum of successive annual growth in diameter was produced. The age of trunk diameter inflection and the age of knot growth inflection were later for better site conditions. The age of trunk diameter inflection and the age of knot growth inflection were later for dominant woods than for average nodule growth. Different site conditions and trunk diameters affected nodule growth, and nodule attributes differed between the two nodule types as trunk diameter grew. Delaying the maximum continuous annual growth by rationally formulating forest management measures can lengthen the duration of trunk growth while extending branch growth, increase the proportion of curved knot to optimize wood quality, and improve wood quality.
    Characteristics of soil carbon, nitrogen, and water of Populus cathayana plantation along different vegetation restoration years in alpine sandy region
    XU Renfei, WANG Lu, DENG Lei, WANG Wenying, DU Sheng, GUAN Jinhong
    2024, 35(10):  2657-2666.  doi:10.13287/j.1001-9332.202410.002
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    As the most effective way to remedy and reconstruct the degraded ecosystems, vegetation restoration could affect soil carbon and nitrogen cycles and water balance. We examined the responses of carbon, nitrogen, and water in 0-200 cm soil layer to vegetation restoration years by analyzing their distribution characteristics across a restoration chronosequence of Populus cathayana plantation (5, 10, 15, 20, and 25 years) in alpine sandy region of the Qinghai-Tibetan Plateau. The results showed that the content and storage of soil organic carbon (SOC) and soil total nitrogen (STN) increased significantly, while that of soil inorganic carbon (SIC) decreased significantly with restoration years. SOC, SIC and STN content for the entire 200 cm soil layer were 0.41-1.24 g C·kg-1, 4.53-8.07 g C·kg-1, and 0.12-0.22 g N·kg-1, respectively. SOC, SIC, and STN storage for the entire 200 cm were 16.08-33.51 t C·hm-2, 187.12-241.02 t C·hm-2, and 4.27-6.66 t N·hm-2, respectively. After 25 years vegetation restoration, the storage of SOC and STN for the entire 200 cm soil layer were significantly increased by 68.1% and 39.6%, while the SIC storage was significantly decreased by 9.5% compared with the 5 years vegetation restoration. The storage of SOC, SIC and STN in the 100-200 cm soil layer were 1.3-1.4 times higher than those in the 0-100 cm layer. The storage of SIC within the 0-200 cm layer was 8.2 times of the SOC storage over the same layer. Compared with the 5 years restoration, SOC storage in the 0-200 cm soil layer of 10, 15, 20, and 25 restoration years increased by 13.3%-68.1%, which were 1.0-2.1 times of the STN storage, suggesting a decoupling of SOC and STN accumulation during restoration. After 15 years vegetation restoration, soil water content and storage peaked at 7.4% and 274.17 mm, respectively. Restoration years were significantly positively correlated with SOC and STN contents, but not related to water content. SOC, STN, and water storage were significantly and positively correlated with each other, resulting in a positive promoting effect between each pair. In conclusion, the inorganic carbon pool was a significant contributor to the total carbon pool in alpine sandy region of the Qinghai-Tibetan Pla-teau. Vegetation restoration year is a primary determinant of soil carbon, nitrogen, and water sequestration, with the contributions of deeper soil layers to regional levels being equally important and can not be ignored. This finding suggested that alpine sandy ecosystems required soil nitrogen input in the early vegetation restoration stages.
    Effect of exogenous paclobutrazol on the drought resistance of Phoebe bournei seedlings under drought stress
    SONG Yanyan, XU Peiyue, HE Gongxiu, HU Kongfei, JI Li, YANG Lili, SUN Honggang, ZHANG Xie
    2024, 35(10):  2667-2676.  doi:10.13287/j.1001-9332.202410.007
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    To clarify the response mechanism of exogenous paclobutrazol on drought resistance in Phoebe bournei seedlings, we investigated the effects of spraying different concentrations of paclobutrazol (25, 50, 100 mg·L-1) on the photosynthetic and antioxidant systems of 2-year-old P. bournei seedlings under drought stress using natural drought method. The results showed that drought stress significantly reduced the photosynthesis and broke the dynamic balance of antioxidant system in P. bournei seedlings. Spraying with different concentrations of paclobutrazol effectively alleviated the negative impacts of drought stress, and enhanced the defense capability of photosynthetic and antioxidant systems, with the 100 mg·L-1 paclobutrazol treatment being the most effective. Under exogenous 100 mg·L-1 paclobutrazol treatment, the total chlorophyll in leaves increased significantly, with a maximum increase of 51.9%. The apparent photosynthetic electron transfer rate, photochemical quenching coefficient and actual photochemical quantum yield were significantly increased, with maximum increase of 67.8%, 58.4%, and 59.7%, respectively. The net photosynthetic rate, stomatal conductance and transpiration rate, were enhanced, reaching maximum increase of 65.5%, 65.4%, and 68.6%, respectively. In summary, exogenous 100 mg·L-1paclobutrazol has the strongest ability to enhance drought resistance of P. bournei seedlings by regulating photosynthetic and antioxidant systems.
    Comprehensive evaluation of resistance to Cd stress in mycorrhizal seedlings formed by different genotypes of Cenococcum geophilum and Pinus massoniana
    ZHANG Xiao, YAN Tianyi, ZHANG Yuhu, WU Aolin, XIE Rongzhang, ZHANG Taoxiang, YANG Wenhao
    2024, 35(10):  2677-2687.  doi:10.13287/j.1001-9332.202410.008
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    To select the mycorrhizal seedlings of Pinus massoniana with excellent Cd-resistance and explore the mechanism of Cenococcum geophilum promoting the resistance to Cd stress of P. massoniana, nine species of C. geophilum isolated from different hosts infected P. massoniana to form mycorrhizal seedlings, were cultured in Cd-contaminated soil for three months. We conducted the principal component analysis (PCA) on biomass, root structure, and photosynthesis, and evaluated the Cd tolerance of mycorrhizal seedlings by membership function. The results showed that dry and fresh weight of mycorrhizal seedlings under Cd stress were 1.0-2.1 and 1.0-1.4 times of that under the control. Root structure of P. massoniana mycorrhizal seedlings was improved by C. geophilum, with root volume and average root diameter being 1.5-2.3 and 1.0-1.3 times of that under the control. Photosynthesis of mycorrhizal seedlings was significantly enhanced by C. geophilum, with photosynthetic rate, stomatal conductance, transpiration rate, and intercellular CO2 concentration of Cg-HS3 being 11.8, 3.5, 3.0, and 0.4 times of that under the control, respectively. The transport of Cd by mycorrhizal seedlings was significantly reduced by C. geophilum, which was 30.4%-73.0% of that under the control. Based on the D value of comprehensive evaluation of Cd tole-rance of mycorrhizal seedlings, and cluster analysis of inter-group linkage, the mycorrhizal seedlings were classified into Cd-sensitive type (Cg-YS4, Cg-HS2, Cg-YS1, Cg-HS1), low Cd-tolerance type (Cg-HS3, Cg-QQ, Cg-YS3, Cg-YS2), and high Cd-tolerance type (Cg-QG). In conclusion, Cg-QG and Cg-HS3 can be used as excellent materials to resist Cd stress and restore the ecological environment in mining area.
    Burial, source characteristics and influencing factors of organic carbon in mangrove sediments at the mouth of the Oujiang River Estuary, China
    LYU Congcong, MA Yadong, SHUI Bonian, YU Yang, LI Bin, LI Xueli, ZHOU Zhongnan, HU Chengye
    2024, 35(10):  2688-2696.  doi:10.13287/j.1001-9332.202410.012
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    Mangrove forests are crucial coastal “blue carbon” ecosystems, known for their significant carbon sequestration capabilities to “carbon neutrality” and mitigating global climate change. We used 210Pb radioisotope dating to analyze sedimentation rates in the sediments of the Oujiang River Estuary mangrove forest, to calculate organic carbon burial rate, and to assess the characteristics and sources of organic carbon burial. The results showed that the average total organic carbon content in the sediments was 1.4 %, generally decreasing with depth. The average organic carbon burial rate was 26.2 Mg C·hm-2·a-1, slightly higher than the global average for mangrove forests. By contrast, the organic carbon content in the core sediments (0-150 cm) was 37.4 Mg C·hm-2, slightly lower than the global average. The stable carbon and nitrogen isotope distribution characteristics and the stable isotope mixing model (SIMMR) indicated that organic carbon originated from a mix of marine and terrestrial sources. Marine sources, such as suspended organic particles and phytoplankton, contributed 45.6% and 10.6%, respectively, while terrestrial sources, including sedimentary organic matter and leaf litter, accounted for 31.5% and 12.3%, respectively. Overall, the Oujiang River Estuary mangrove forest had a high organic carbon burial rate, with significant variations in carbon content at different depths influenced by tidal influences. Additionally, the input of external suspended organic particles was an important contributor to sediment organic carbon burial.
    Quantitative classification and biodiversity characteristics of plant communities in Luoshan Mountain steppe, Ningxia, China
    LI Qianfei, SHEN Yan, MA Hongbin, XIONG Zeqin, WANG Guohui, HUO Xinru, LI Wen
    2024, 35(10):  2697-2706.  doi:10.13287/j.1001-9332.202410.004
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    To understand the distribution pattern and influencing factors of plant community and diversity along the altitude gradient, we examined plant community types, plant diversity and phylogenetic diversity of mountain steppe in Luoshan, Ningxia, and analyzed the relationship between the plant community and its diversity and environmental driving factors. The results showed that the main community types in the mountain steppe were Asterothamnus centraliasiaticus community, Caragana tibetica community, Convolvulus tragacanthoides community, Stipa bungeana community, Stipa brevifloraAjania achilloides community, Artemisia frigida community, Roegneria alashanicaS. brevifloraHedysarum polybotrys community, S. brevifloraStipa grandis community, S. grandisS. bungeana community, Cyperus glomeratus community, S. grandis community and Carex aridula community. The distribution of mountain steppe community was mainly affected by altitude, soil alkali-hydrolyzed nitrogen, water content, available potassium, silt and organic matter contents, with altitude and soil water content having the greatest effects (P<0.01). The Patrick index and phylogenetic diversity index (PD) of plant community showed an increasing trend with the altitude increase, the Shannon index and Pielou index showed a unimodal trend, and the phylogene-tic structure gradually changed from aggregation to dispersion. There was a significant positive correlation between species diversity index and PD index. Shannon index was negatively correlated with net relatedness index (NRI). Plant species diversity and phylogenetic diversity of mountain steppe were mainly affected by soil water content, available potassium, total nitrogen, silt and sand contents. NTI was significantly affected by altitude, while the NRI index was significantly affected by soil silt content.
    Changes of climate niche of Solidago canadensis during its invasion in China
    ZHANG Xianrui, LI Xindi, CHEN Yu, ZHANG Chunling, WANG Jia, SONG Xingjiang, SONG Yuhang, LIU Gang
    2024, 35(10):  2707-2714.  doi:10.13287/j.1001-9332.202410.001
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    Niche conservatism is essential for predicting the risk of alien species invasions. Currently, the changes of climate niche of Solidago canadensis during its invasion in China are still not clear. Using principal component analysis, we examined the climate niche shifts of S. canadensis during its invasion and analyzed its potential distribution in China. The results showed that, throughout its invasion in China, S. canadensis retained the climate niche characteristics of its native range (Stability index: 0.776), exhibiting strong niche conservatism. However, there were notable differences between the climate niches of the invasive and native populations. Such differences were primarily caused by the high level of niche unfilling (Unfilling index: 0.818) in its climate niche. Moreover, a certain degree of niche expansion (Expansion index: 0.224) was observed. These indicated that the invasion of this species was far from saturation and still had significant potential for further expansion in China. Therefore, the climate niche of S. canadensis primarily exhibited a conservative state after invading China, but there was also a certain degree of niche shift. S. canadensis was mainly in a stable invasion stage in East, Central, South, and Southwest China, while it was in a localized adaptation stage in the North and West China. These regions were the focus areas for prevention and control measures against S. canadensis in the future. The main climatic factors affecting the distribution of S. canadensis were precipitation of the driest month and mean temperature of the coldest quarter. During its invasion in China, the climate niche of S. canadensis shifted towards areas with higher temperature in the coldest quarter, drier in the dry season, and more precipitation in the warm and humid seasons. In conclusion, our results suggested that S. canadensis has strong adaptability, and the expansion of climate niche may further promote its invasion in China.
    Effects of exogenous abscisic acid on grain filling characteristics, starch accumulation, and endogenous hormones in maize under early post-anthesis high temperature stress
    YU Tao, XIN Yuning, WANG Jun
    2024, 35(10):  2715-2724.  doi:10.13287/j.1001-9332.202410.005
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    We investigated the effects of exogenous abscisic acid (ABA) on grain filling, starch accumulation, and endogenous hormones in maize (both the heat-tolerant maize variety Zhengdan 958 (ZD958) and the heat-sensitive variety Xianyu 335 (XY335)) under early post-anthesis high temperature stress by simulating high temperature stress for a period of 6 to 12 days post-anthesis in 2022 and 2023. There were three treatments: spraying water at ambient temperature as the control, spraying water at high temperature, and spraying ABA at high temperature. The results showed that early post-anthesis high temperature stress resulted in a significant reduction in grain weight and yield in maize, with XY335 showing a greater reduction than ZD958. The application of ABA mitigated the effects of high temperature stress on grain weight and yield, with the mean yield of ZD958 and XY335 over the two years being increased by 9.6% and 12.3%, respectively. High temperature stress inhibited the activities of enzymes involved in starch synthesis in the grain, resulting in reduced starch content. In contrast, ABA application after high temperature stress increased the activities of sucrose synthase, ADP-glucose pyrophosphorylase, granule-bound starch synthases, soluble starch synthase, and starch branching enzyme, thereby promoting starch accumulation. High temperature stress disturbed the balance of endogenous hormones in the grain, resulting in inhibition of grain filling, whereas ABA application mitigated the adverse effects of high temperature stress on endogenous hormone levels by increasing zeatin riboside, indole-3-acetic acid, and ABA levels and decreasing gibberellin level, which increased grain filling rate, prolonged filling duration, and improved filling characteristics. The grain filling characteristics, starch accumulation, endogenous hormone levels, and grain yield were more sensitive to exogenous ABA regulation in XY335 than in ZD958 under early post-anthesis high temperature stress. In conclusion, exogenous ABA could improve maize grain filling characteristics, promote starch accumulation, and regulate endogenous hormone levels, and ultimately increase grain weight and yield under early post-anthesis high temperature stress.
    Effects of different tillage measures on soil organic carbon in dryland wheat fields on the Loess Plateau, Northwest China based on meta-analysis
    HUANG Xiao, WANG Longxin, XU Tianjing, YAN Qiuyan, YAN Shuangdui, DONG Fei, QI Chen, ZHANG Minmin
    2024, 35(10):  2725-2732.  doi:10.13287/j.1001-9332.202410.011
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    To evaluate the effects of tillage measure on soil organic carbon (SOC) and influence degree of various factors on relative change rate of SOC at regional scale, we conducted a meta-analysis to investigate the impacts of tillage measures (CK, traditional deep tillage without straw return; NTS, no tillage with straw return; NT, no tillage without straw return; TS, traditional tillage with straw return; SS, subsoiling tillage) on SOC content and influence factors (climate conditions, soil types, cultivation types, and initial soil physicochemical properties) on relative change rate of SOC in dryland wheat fields on the Loess Plateau, based on literatures published during 2000-2023. Results indicated that NT, NTS, SS and TS performed varies positive effect on SOC content in 0-20 cm soil layer compared with CK. In addition, greater enhancement of SOC were obtained in conditions of loessal soil, mid-temperate zone, average annual temperature of ≤10 ℃ and average annual rainfall of ≤500 mm. It was favorable to carbon sequestration when the initial SOC ≥10 g·kg-1, alkaline nitrogen ≥60 mg·kg-1, available phosphorus ≥20 mg·kg-1 and available potassium ≥120 mg·kg-1. However, accumulation of SOC could be weakened under higher total nitrogen content (≥1 g·kg-1). In conclusion, NTS treatment performs better carbon sequestration effect in the topsoil and can be used as suitable tillage measure in dryland wheat fields on the Loess Plateau region.
    Effect of enhanced silicate minerals weathering on carbon sequestration by plant-soil systems in rice fields
    WANG Fangna, ZHU Feifei, LI Yinghua, LIU Deze, QU Yuying, QIN Yujing, WANG Ying-ying, WANG Wenchao, XIE Jin, FANG Yunting
    2024, 35(10):  2733-2743.  doi:10.13287/j.1001-9332.202410.017
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    Successive crop harvest results in soil silicon (Si) loss, which constantly reduces soil available Si. Agricultural measures that can increase the availability of soil Si are in urgent need in agroecosystems. Enhanced weathering of silicate minerals can effectively replenish soil Si, which will promote plant uptake of Si, formation of plant phytolith occluded carbon (PhytOC), and the sequestration of atmospheric CO2. In addition, the process of silicate mineral weathering can promote soil carbon (C) sequestration. In this study, we applied silicate mineral wollasto-nite powder to rice fields in Liaoning Province to investigate effects of the enhanced weathering process on soil available Si, changes in phytolith carbon (PhytOC) content in plant-soil systems, and the content of various soil C forms. The results showed that the application of wollastonite powder could significantly increase the available Si content in the surface soil (53%), promote rice dry biomass production (12% increase in rice grains and 4% increase in straw), increase the phytOC content (4% increase in rice grains and 26% increase in straw), which together resulted in 25% increase in phytOC production fluxes. The application of wollastonite powder tended to increase both inorganic and organic C content in the soil, resulting in 13% increases of soil total C content. In summary, enhanced weathering of silicate minerals could effectively increase soil available Si in paddy soil, promote rice Si absorption and phytOC formation, and enhance soil CO2 sequestration, achieving the effect of coordinated carbon sequestration from both above- and below-ground.
    Impacts of freeze-thaw process on soil microbial nutrient limitation in slope farmlands of the Chinese Mollisol region
    AN Xiaobing, ZHENG Fenli, WANG Xuesong, YANG Xinyue, LIANG Rui, WANG Lun
    2024, 35(10):  2744-2754.  doi:10.13287/j.1001-9332.202410.014
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    Understanding the impacts of freeze-thaw action on soil microbial nutrient limitation can provide important support for sustainable utilization of black soil resources. We analyzed the impacts of freeze-thaw action on soil microbial nutrient limitation on a slope farmland located in a typical thick Mollisol region of Keshan County, Heilongjiang Province. We examined the responses of soil microbial nutrient limitation to soil erosion rates through measuring soil nutrient, soil microbial biomass, and soil enzyme activities before and after freeze-thaw under natural conditions, and estimated the soil erosion rates by 137Cs tracing technology. The results showed that: 1) soil erosion rates of slope farmland ranged from 479.31 to 7802.33 t·km-2·a-1, with an average value of 2751.02 t·km-2·a-1. 2) Under freeze-thaw process, soil water-soluble organic nitrogen and microbial biomass carbon (MBC) of slope farmland significantly decreased by 27.9% and 37.3%, respectively. However, the freeze-thaw process did not affect soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP), water-soluble organic carbon, soil available phosphorus, microbial biomass nitrogen and phosphorus. 3) Under freeze-thaw action, the activities of β-1,4-glucosidase, L-leucine aminopeptidase and β-1,4-N-acetyl-glucosaminidase significantly decreased by 43.2%, 11.0%, and 25.5%, respectively. The results of the enzyme quantification vector model indicated that soil microorganisms were limited by carbon and phosphorus availability. The freeze-thaw action weakened the relative carbon limitation of soil microorganisms and strengthened the phosphorus limitation. 4) The structural equation model analysis indicated that freeze-thaw action had a direct positive effect on relative phosphorus limitation and a negative effect on relative carbon limitation in soil microorganisms. Soil erosion rates had a direct negative effect on relative carbon limitation of soil microorganisms. 5) Soil erosion rates had significantly negative influences on SOC and TN before and after freeze-thaw, TP after freeze-thaw, MBC after freeze-thaw, and vector length before freeze-thaw. Overall, freeze-thaw action reduced the activities of soil carbon and nitrogen acquisition enzymes and further changed the resource limitation of soil microorganisms. Our results could improve the understanding of the mechanisms regarding freeze-thaw action impact on the limitation of soil microbial resource in the Chinese Mollisol region and provide scientific support for nutrient management of slope farmland.
    Changes of soil microbial phospholipid fatty acid in soil profile under different land use types
    MA Xuman, YU Xiaomeng, WANG Weipeng, MENG Yaxin, XU Xuehua
    2024, 35(10):  2755-2764.  doi:10.13287/j.1001-9332.202410.016
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    We elucidated the changes of soil microbial biomass and community structure in soil profiles under four typical land use types (farmland, grassland, Betula platyphylla secondary forest and Larix principis-rupprechtii plantation)and across five soil layers (0-10, 10-20, 20-30, 30-40, 40-50 cm) in the northern mountainous region of Hebei Province. We measured soil microbial biomass by phospholipid fatty acid (PLFA) method, and investigated the effects of land use and soil depth on soil microbial biomass and community structure by variance analysis, correlation analysis and redundancy analysis. The results showed that soil water content, bulk density, and organic carbon content of farmland differed significantly from other land use types. The content of PLFA in farmland was significantly lower than that in other land use types. The Gram-positive bacteria/Gram-negative bacteria (G+/G-) in farmland were higher, and the nutrient stress was greater. With the increase of soil depth, soil water content, organic carbon, total nitrogen, total phosphorus and microbial biomass of the four land use types showed a decreasing trend. In grassland, secondary forest and plantation, G+/G- was larger in deep soil than top soil. Except for grassland, the bacteria/fungi was smaller in deep soil than top soil. Correlation analysis and redundancy analysis showed that soil bulk density, natural water content and organic carbon were the main environmental factors affecting microbial communities in the four land use types. Our results would provide theoretical basis for the optimization of land use structure in the northern mountainous region of Hebei Province.
    Isolation, screening of zinc solubilizing microorganisms and its application in low zinc calcareous soil
    LI Yanlin, CHEN Juan, CHU Lili, ZHU Pengchao, FU Yirui, HUANG Donglin, ZHANG Dabin, GAO Yajun, WANG Zhaohui
    2024, 35(10):  2765-2774.  doi:10.13287/j.1001-9332.202410.010
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    Inoculating zinc solubilizing microorganisms (ZSMs) is considered as a promising strategy for increasing Zn phytoavailability in soils with low Zn availability. In present study, we screened six strains of ZSMs from rhizosphere of green manure crop, including three strains of fungi, Talaromyces purpureogenus, Talaromyces pinophilus, and Penicillium amestolkiae, and three strains of bacteria, Cellulosimicrobium funkei, Isptericola cucumis and Streptomyces canus. We conducted a pot experiment of Bok choy inoculated with different ZSMs to analyze the Zn content in shoots and roots, and compared the Zn solubilizing effect of ZSMs. The results showed that Zn content in the roots and leaves of Bok choy of treatments inoculated with ZSMs were increased by 15%-44% and 27%-62%, respectively, and that soil DTPA-Zn concentration were increased by 52%-359%. The treatment inoculated with P. amestolkiae had the best effect. ZSMs significantly enhanced root uptake of Zn and foliar Zn content through increa-sing DTPA-Zn by mobilizing soil Zn by transformation of moderately available Zn (Zn bounded with manganese oxide and Zn strongly bounded with organic matter) to available Zn (exchangeable fraction, Zn bounded with carbonate, and Zn bounded with loose organic matter). The screened Zn mobilizing fungi averagely enhanced soil Zn phytoavailability and leaf Zn content by 240% and 46%, showing superior mobilizing ability than screened bacteria. P. amestolkiae significantly increased Zn content of soil and plant, thus it could be a promising potential microorganism as biofotification agent.
    Soil health evaluation of loquat orchard based on soil quality index method
    CUI Xintao, XIAO Mouliang, ZHAO Yuxiao, WU Yuping, WU Bibo, QI Lin, LI Hemeng, YU Chaoxu, LU Shunbao, ZHANG Yanjie, GE Tida
    2024, 35(10):  2775-2784.  doi:10.13287/j.1001-9332.202410.013
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    Fruit quality and yield in orchards will decrease after long-term planting. To analyze the changes of soil quality under different planting years and identify the key factors of the declining of orchard soil quality could provide scientific foundation for optimizing fertilization management of orchard soil. In this study, we analyzed the changes of soil physical, chemical, and biological properties of loquat orchard under different planting years (<10 years, 10-15 years, 15-20 years, ≥20 years) in Ninghai County, Zhejiang Province, and evaluated soil health by using soil quality index, multifunctionality index, and sensitivity and resistance indicators. The results showed that, compared with the orchards planting less than 10 years, soil bulk density in the orchards with planting years of 10-15 years and over 20 years increased by 12.8% and 13.6%, respectively. Soil pH decreased by 8.8%, 8.6%, and 7.5% in the orchards with planting years of 10-15 years, 15-20 years and over 20 years, respectively. With the increase of planting years, soil microbial biomass carbon, soluble organic carbon, soluble organic nitrogen, available phosphorus, available potassium, total organic carbon, total nitrogen decreased, and the soil quality and multifunctionality index of loquat orchard soil decreased. Compared with the orchards planting less than 10 years, soil quality index and soil multifunctionality index decreased by 20.4% and 17.9% for the orchards with the planting years of 10-15 years, 38.1% and 25.2% for the orchards with the planting years between 15-20 years, and 50.7% and 35.5% for the orchards planting over 20 years, respectively. The key factors affecting soil quality of loquat orchards were soil soluble nitrogen, available potassium, and available phosphorus. Amongst the available nutrients, NH4+ and NO3- were the sensitive indices in orchard soil. In conclusion, long-term planting decreased soil quality and available nutrient content in loquat orchards.
    Soil health evaluation of non-grain cultivated land: A case study of Dongwu Town, Ningbo City, Zhejiang Province, China
    ZHAO Yuxiao, XIAO Mouliang, CUI Xintao, LU Shunbao, WANG Shuang, ZHU Zhenke, ZHANG Yanjie, GE Tida
    2024, 35(10):  2785-2793.  doi:10.13287/j.1001-9332.202410.018
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    Non-grain utilization of cultivated land threatens farmland ecological environment and soil health, which restricts grain production. To identify the key obstacle factors of cultivated soil under non-grain utilization, explore the changes of soil quality and function, and evaluate the effects of non-grain utilization on the health of farmland soil, we evaluated soil health of farmland under different non-grain utilization types (vegetables, bamboo-abandoned, nursery-grown plant-abandoned, nursery-grown plant-rice) by soil quality index and soil multifunctionality index method combined with sensitivity and resistance approaches. The results showed that soil organic carbon and total nitrogen (TN) in the bamboo-abandoned soil were 95.3%, 66.7%, 65.7% and 82.6%, 57.0%, 59.5% of those under vegetables, nursery-grown plant-abandoned and nursery-grown plant-rice treatments, respectively. The electrical conductivity of vegetable soil was 2.2-2.5 times that of other soils of non-grain cultivated land. Total phosphorus and nitrate nitrogen were 1.8-2.0 times and 3.5-5.5 times of other soils of non-grain cultivated land, respectively. Among different non-grain utilization types, soil quality index and soil multifunctionality index of vegetable soil were the highest. Soil quality index and soil multifunctionality index decreased significantly in bamboo-abandoned (50.2% and 22.7%), nursery-grown plant-abandoned (38.3% and 14.4%) and nursery-grown plant-rice (27.7% and 8.5%) treatments, compared with that of vegetable soil. Random forest model analysis showed that available potassium and available nitrogen (AN) were the key factors affecting soil quality index. TN, cellulase and xylanase activities that related to soil C cycle were the key factors affecting soil multifunctionality index. In addition, available phosphorus, AN, TN and enzyme activity were sensitive indices to soil change in non-grain cultivated land. By comprehensively evaluating soil quality of non-grain cultivated land, we identified the key obstacle factors and provide a theoretical basis for the healthy soil cultivation and sustainable utilization of non-grain cultivated land.
    PLSR model based on near-infrared spectroscopy for the detection of wood fiber anatomy of Schima superba.
    LIN Chengfu, SHAO Wen, WANG Jiayi, ZHANG Rui, MA Lizhen, HUANG Shaohua, FAN Huihua, ZHOU Zhichun
    2024, 35(10):  2794-2802.  doi:10.13287/j.1001-9332.202410.003
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    To rapidly acquire fiber phenotypic data for wood quality assessment, we used a portable NIR spectro-meter to collect spectral data in 100 individuals of Schima superba at 18-year-old of 20 different provenances, and simultaneously collected wood cores. Wood basic density and the anatomical structure of wood fiber were measured. The standard normal variate (SNV), orthogonal signal correction (OSC), and multiplicative scatter correction (MSC) methods were used for spectral preprocessing, the competitive adaptive reweighted sampling (CARS) method were used for wavelength selection, and the partial least squares regression (PLSR) model were established. The results showed a significant difference for the absolute reflectance data between forest and indoor environments, and the spectral data of which were relatively independent. SNV, OSC and MSC showed significant differences for predictive performance of the model. OSC had the excellent preprocessing capability in multiple cha-racteristics of wood fiber ether in forest and indoor environments. The predictive accuracy of the models with R2 was 0.47-0.78 in forest (average=0.63), and R2 was 0.54-0.82 in indoor environment (average=0.71). However, the SNV and MSC methods could not establish the models, except the fiber wall-cavity ratio from forest data. After wavelength selection through the CARS method, the predictive accuracy of the models was significantly improved using both forest and indoor data (R2=0.58 and 0.72, respectively). When performed OSC before and after CARS, the predictive accuracy of the models was improved to 0.68 and 0.84 respectively using forest and indoor data. The OSC and CARS could significantly improve the accuracy of the models for wood fiber anatomical structures. First OSC, then CARS, and finally OSC methods could be used to establish the PLSR model for fiber length, fiber cell wall thickness, fiber lumen diameter, wood basic density, fiber cavity-width ratio, and fiber wall-cavity ratio, and the R2 ranged from 0.80 to 0.95. These models had effective predictive ability and accuracy to assess the physical properties of wood fibers of S. superba.
    Spatiotemporal dynamics of forest cover and its response to climate change in Shandong Province, China during 2000-2022.
    CAO Yue, LI Hao, ZHANG Chunhua, LI Yunyuan, WU Jingqi, CHAI Xinyuan, NIU Jinzheng, TAO Yujun
    2024, 35(10):  2803-2812.  doi:10.13287/j.1001-9332.202410.024
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    Accurately capturing the spatiotemporal dynamics of regional forest cover and its response to climate change is of great significance for forest resource management and ecological environment protection. We used statistical methods such us linear regression and correlation analysis, as well as remote sensing change monitoring to investigate the spatiotemporal dynamics of forest cover and its response to climate change from 2000 to 2022 in Shandong Province based on MODIS VCF products and meteorological data. The results showed that the forest co-verage and forest area in Shandong Province increased from 43.0% and 197.06×104 hm2 in 2000 to 43.1% and 326.08×104 hm2 in 2022, respectively. Spatially, forest coverage grew stepwise from the southwest and northwest to the center and east of Shandong. 90.6% of the forest area of Shandong Province experienced a relative increase in forest cover during 2000-2022. Most of the increased area was concentrated in the central southern mountains and hills and the eastern low mountains and hills. The area expansion of forest cover was primarily located in the lowland areas of Liaocheng, Dezhou, Heze, Jining, and Binzhou, which accounted for 52.3% of the provincial forest area. There was a positive correlation between forest coverage and air temperature, but a negative correlation between forest coverage and precipitation. Air temperature was the main climatic factor influencing the shift in forest coverage during the study period.
    Impact of climate change on the potential geographical distribution of Hippophae rhamnoides subsp. sinensis
    WANG Wenqiang, YANG Bo, LI Xiaowei, LIANG Yongliang, LI Jingyao
    2024, 35(10):  2813-2821.  doi:10.13287/j.1001-9332.202410.025
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    Hippophae rhamnoides subsp. sinensis is an important resource plant with considerable medicinal, economic, and ecological value, and an indicator species in the transition zones between forests and grasslands. Predicting the potential geographic distribution of H. rhamnoides subsp. sinensis under climate change can reveal the responses of China’s grassland and forest to global climate change, which is of significance for the conservation and development of its resources. We utilized distribution data of H. rhamnoides subsp. sinensis to predict its suitable habitats under future climate change based on the Biomod2 ensemble model, and analyzed the trend of land use type change in these habitats in conjunction with remote sensing data of land use types in China in 2020. The results showed that the Biomod2 ensemble model significantly improved the accuracy and precision of predicting H. rhamnoides subsp. sinensis compared to single models. The distribution of H. rhamnoides subsp. sinensis was primarily concentrated on both sides of the diagonal from Liaoning to Tibet, situated in forest-grassland ecotone. Under the SSP126 scenario, the suitable habitats for H. rhamnoides subsp. sinensis would initially expand and then contract. Under the SSP585 scenario, they would show a continuous expansion trend. In the context of global warming, the suitable habitats for H. rhamnoides subsp. sinensis would expand. By 2050 and 2070, the area of suitable habitats for H. rhamnoides subsp. sinensis in grasslands would increase, while areas currently occupied by forests, croplands, and developed land would continue to decrease. Under future climate change, the distribution center of H. rhamnoides subsp. sinensis would migrate towards higher-altitude grassland areas. Among the environmental factors affecting the distribution of H. rhamnoides subsp. sinensis, climate variables were predominant, with the highest contribution of rainfall during the warmest season.
    Construction of regional ecological security pattern based on the “sensitivity-importance-connectivity” framework: A case study of Guizhou Province
    GAO Zuqiao, LI Changbin, YANG Zhiyuan, WANG Yifei, SHEN Na, ZHANG Xuyang, LI Meijing, LIU Yuanwen
    2024, 35(10):  2822-2832.  doi:10.13287/j.1001-9332.202410.019
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    The construction of an ecological security pattern is crucial to maintain ecosystem health and stability, with great significance for regional sustainable development. Following the research paradigm of “ecological source areas-ecological resistance surfaces-ecological corridors”, based on the index framework of “sensitivity-importance-connectivity”, we identified the ecological source areas, generated the ecological resistance surface through graded weighting of underlying surface factors and point of interest (POI) method, determined the ecological corridor, pinch point, and obstacle area using circuit theory, and constructed the ecological security pattern of Guizhou Pro-vince. Results showed that the areas of extremely sensitive of rocky desertification and soil erosion and the areas of extremely important areas of water resources forming, soil and water conservation and biodiversity in Guizhou Pro-vince were generally small and distributed differently, accounting for 1.6%, 3.7%, 25.2%, 6.1%, and 10.4% of the total area, respectively. The key ecological functional areas of the extremely sensitive to external disturbance, most important in ecosystem service and strongly connective in landscape accounted for 5.3%, 34.2%, and 27.9%, respectively. A total of 210 ecological source areas were identified, covering 27574.38 km2 and with an area ratio of 15.6%. The number of the ecological corridor was counted into 463, with a total length of 10049.81 km. The amount of ecological pinch points was 490, while that of the ecological barrier was 117, area of the both were computed into 22.08 and 91.04 km2, respectively. Ecologically high-resistance areas were mainly distributed in regions with highly frequent human activities. Based on the above construction, we assessed the ecological security pattern in Guizhou Province, conducted ecological security zoning, and proposed targeted protection and restoration mea-sures. The study could provide scientific references for the spatial planning of land and regional ecological protection in Guizhou Province.
    Land use changes and driving forces of landslide area in Tongwei County, Gansu Province, Northwest China from 1985 to 2020.
    JIA Jing, SU Xing, ZHANG Jun, LU Changliang, ZHANG Manyin, LI Xia, DONG Yaogang, REN Haochen
    2024, 35(10):  2833-2841.  doi:10.13287/j.1001-9332.202410.020
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    Accurately analyzing the type of land use and change characteristics of disaster damage in landslide areas is of great significance to scientifically promote the optimization of regional land use pattern and disaster prevention and mitigation. We analyzed the characteristic parameters of landslides as well as the characteristics and driving factors of land use change from 1985 to 2020 in Tongwei County, Gansu Province, using ALOS DEM data and 1985-2020 land use data, GIS spatial analysis, land-use dynamic attitude, transfer matrix, and Geodetector. The results showed that a total of 1012 landslide samples were identified, characterized by medium elevation, gentle gradient, low elevation difference, short length, and small size. During 1985-2020, landslide area land use types were cropland, woodland, grassland, bare land and impervious surface, dominated by grassland and cropland. During 2015-2020, each category of single land use dynamic attitude reached the largest, with the value of cropland, grassland, woodland, bare land, and the combined land use being 3.1%, 3.0%, 10.9%, 20.0%, 1.5%, respectively. During the study period, land use change was dominated by cropland and grassland, with a total reduction of 4.39 km2 in cultivated land area, which was converted into grassland and forest. There was no change in bare land and impervious surfaces. We investigated the driving factors of land use change across 2000-2005 and 2015-2020. Slope and normalized difference vegetation index had a stronger explanatory power for land use change during 2000-2005, while slope, population density and total population had a stronger explanatory power during 2015-2020. The land use mode of regional individual landslide tended to be unified, and the increase of grassland enhanced the vegetation cover of the region. The findings would provide a scientific basis for the development and reuse of disaster damaged land and ecological restoration.
    Spatial and temporal evolution and multi-scenario modeling of land use and habitat quality in highland mountainous urban agglomeration of central Yunnan, Southwest China
    YU Han, WU Yingmei, LI Chen, WANG Min, ZHOU Yan
    2024, 35(10):  2842-2852.  doi:10.13287/j.1001-9332.202410.021
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    There are obvious contradictions between the development of plateau mountain urban agglomerations and the protection of ecological environment, with the quality of habitat being closely related to land use changes during urbanization. Based on the land use data of central Yunnan urban agglomeration in 2000, 2010, and 2020, we analyzed the spatio-temporal variations of land use and habitat quality, and used PLUS model and InVEST model to predict the status of land use and habitat quality in 2030 under three scenarios: natural development, urban deve-lopment, and ecological protection. The results showed that the artificial surface area of the study area increased significantly from 2000 to 2020, mainly distributed in the areas with very low and medium topographic gradients, most of which were transformed from the cultivated land in the dam area with slow slope. Habitat quality decreased significantly, especially from 2010 to 2020. The area with extremely high habitat quality decreased significantly, while the area with very low habitat quality and low habitat quality increased significantly. In the three scenarios, under the ecological protection scenario, the area of extremely low habitat quality would be the smallest, the area of extremely high habitat quality would be the largest, and the area of deterioration would be the least in 2030, which was more in line with the high-quality economic and social development of the central Yunnan urban agglomeration.
    Assessment of habitat quality changes and driving factors in Jilin Province based on InVEST model and geodetector
    XIN Peiyuan, TIAN Tian, ZHANG Meilu, HAN Weizheng, SONG Yunting
    2024, 35(10):  2853-2860.  doi:10.13287/j.1001-9332.202410.026
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    Jilin Province is an important ecological security barrier in Northeast China as it is located at the junction of the Northeast forest belts and the northern sand prevention belts. In recent years, Jilin Province has actively carried out ecological protection and restoration projects, resulting in a continuous improvement trend for the overall ecological environment. However, the evolution patterns and mechanisms of habitat quality are largely unkown. We applied the InVEST model and geographic detector method to analyze the changes in habitat quality and evaluate the main driving factors from 2000 to 2020. The results showed that the average habitat quality in Jilin Province showed a slight downward trend, and that the spatial heterogeneity characteristics of habitat quality in east and west gradually increased. The degree of habitat degradation presented a single nuclear radiation pattern centered on Changchun City. Vegetation factors and terrain factors were the first and secondary causes of spatial heterogeneity of habitat quality, respectively. The average habitat quality within the eco-redline of Jilin Province was showing an increasing trend year by year, which was consistent with the overall distribution of regions with extremely high habitat quality levels. There was a local spatial dislocation (the phenomenon of extremely high habitat quality levels not within the eco-redline) in the eastern part of Jilin Province. Our results could provide reference basis for ecosystem protection and the spatial pattern optimization.
    Ecological environment quality evaluation based on water benefit-based ecological index in Guangdong Province, China
    HU Landi, TAN Juan, CHEN Chulin, SHE Jiyun
    2024, 35(10):  2861-2871.  doi:10.13287/j.1001-9332.202410.023
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    As one of the provinces with the largest number of national forest cities, all prefecture-level cities in Guangdong Province have joined the campaigns of building forest cities. Mastering the spatial and temporal variations of ecological environment quality (EEQ) in Guangdong Province is conducive to the benign interaction and coordinated development of urban construction and ecosystem. We used the water benefit-based ecological index (WBEI) to achieve rapid monitoring of EEQ in Guangdong Province, utilized the standard deviation ellipse and gravity center migration, Theil-Sen Median trend method and Mann-Kendall test to explore the spatial distribution disparities and trends, and analyzed the coupling coordination between EEQ and urbanization. The results showed that the WBEI derived from the normalized difference vegetation index could better reflect vegetation coverage in Guangdong Province, and objectively evaluate the EEQ of watersheds and urban vegetation zones. The EEQ in the northern inland area was generally better than that in the southern coastal area, and it was more concentrated in the southwest-northeast direction. The gravity center position displayed a sequential movement from southwest to northeast and then back to southwest. Most prefecture-level cities remained stable or improved in EEQ, while the improved and degraded types were distributed in various regions of the province. The coupling coordination degree between EEQ and urbanization in southern Guangdong Province exceeded that of the northern region, with the coupling coordination degree being constantly improving. The Pearl River Delta Forest City Cluster emerged as a region characterized by high levels of coupling coordination, with a good radiation driving effect in promoting the coordination of EEQ and urban construction. This study could provide a method reference for EEQ evaluation within multi-watershed forest cities.
    Relationship between Benggang erosion and landscape pattern in the southern red soil zone based on path analysis
    HE Yue, HUANG Yanhe, LIN Jinshi, LIN Xiaohui, JI Xiang
    2024, 35(10):  2872-2880.  doi:10.13287/j.1001-9332.202410.027
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    Benggang (collapsing hill) erosion is one of the most serious ecological problems in the south of China. Understanding the relationship between Benggang erosion and landscape pattern is conducive to the study of Benggang occurrence and development from the perspective of landscape ecology, with great significance for Benggang prevention and ecological protection. We classified the Lanxi River Basin in Anxi County, Fujian Province into 32 small watersheds. 16 landscape pattern indices were selected from five aspects, including landscape shape, fragmentation, connectivity, diversity, and quantitative structure. We analyzed the relationship between Benggang erosion and landscape pattern and its mutual influence by dividing the types of landscape in the sub-watersheds. The results showed that the maximum patch index, aggregation index, spreading index, and patch combination index were representative for characterizing the regional landscape pattern. Based on those characteristics, the sub-watersheds in the study area were classified into two categories, i.e. high-disturbance and low-disturbance. In the high-disturbance sub-watersheds, the correlation between Benggang erosion and landscape shape, fragmentation, and connectivity was significant (Moran’s I of 0.595, 0.605, and -0.545, respectively), indicating that the more irregular and fragmented the landscape shape, the lower the connectivity between the landscapes, the more prone to Benggang erosion. In the low-disturbance sub-watersheds, the correlation between Benggang erosion and fragmentation, connectivity, and diversity were significant (Moran’s I of -0.482, -0.322, and 0.498, respectively), indicating that the higher the degree of aggregation and connectivity between landscapes, and the lower the degree of fragmentation, the less prone to Benggang erosion. For the effect of landscape pattern on Benggang erosion, regardless of high and low-disturbance sub-watersheds, the more complex the landscape shape, the more dispersed and fragmented the distribution was, the more likely it was to promote Benggang erosion. For the effect of Benggang erosion on landscape pattern, the high-disturbance sub-watersheds were more susceptible to the effect of Benggang erosion than the low-disturbance sub-watersheds, which would make the landscape shape more complex, the fragmentation degree increase, and the connectivity degree decrease. Our results can not only provide reference for the prevention and control of erosion, but also provide new ideas for the ecological management of small watersheds in southern China.
    Relationship between the resource density of Larimichthys polyactis and the habitat environment factors in summer in Jiangsu coastal waters, China
    ZHU Haichen, TANG Jianhua, WU Lei, SHI Jinjin, YAN Xin, WANG Chuqing, WANG Yanping, GE Hui
    2024, 35(10):  2881-2886.  doi:10.13287/j.1001-9332.202410.030
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    To understand the habitat distribution characteristics of Larimichthys polyactis in summer in Jiangsu coastal waters, we analyzed the relationship between resource density and habitat environment of L. polyactis by using a two-stage generalized additive model based on the survey data of fishery resources in August 2022, combined with the data of bottom water temperature, bottom salinity, depth, chlorophyll-a and prey species. The results showed that the average resource density of L. polyactis in summer was 15.03 kg·km-2, which mainly distributed in the outer sea area of Lusi Fishing Ground and the middle sea area of Haizhou Bay Fishing Ground. The occurrence probability of L. polyactis was mainly affected by water depth and chlorophyll-a, with the contribution rate of water depth and chlorophyll-a being 40.8% and 10.2%, respectively. The resource density was mainly affected by water depth, chlorophyll-a, bottom salinity and the abundance of Chaemrichthys stigmatias. The bottom salinity was the variable with the largest deviation explanation (19.4%). Our results suggested that resource density of L. polyactis is closely related to its physiological habits, marine environment and the distribution of prey species.
    Investigating jellyfish diet with DNA macrobarcoding: A case study in Rhopilema esculentum
    CHEN Bailing, LI Yulong, BAO Xiangbo, ZHOU Zunchun, LI Yunfeng
    2024, 35(10):  2887-2896.  doi:10.13287/j.1001-9332.202410.032
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    We investigated food composition and feeding selectivity of jellyfish (Rhopilema esculentum) from the coastal aquaculture ponds in Liaodong Bay by DNA metabarcoding technology. The DNA from environmental water samples and stomach contents of R. esculentum were extracted and sequenced by high-throughput sequencing with 18S rDNA V4 region and mitochondrial cytochrome c oxidase subunit I (COI) as metabarcoding markers. Based on 18S rDNA metabarcoding, we detected 27 phyla in the stomach contents of R. esculentum, in which Mollusc was the dominant phylum followed by Arthropod, and 34 phyla in the environmental water samples, in which Pyrrophyta was the dominant phylum followed by Ciliophora and Ascomycota. Using COI metabarcoding, 18 phyla were detected in the stomach contents of R. esculentum, with Mollusc as the dominant phylum and followed by Arthropod. 22 phyla were detected in the environmental water samples, in which Proteobacteria was the dominant phylum followed by Pyrrophyta and Arthropod. Results of both methods indicated R. esculentum food included Mollusc, Arthropod, Streptophyta, Ciliophora, Pyrrophyta, Bacillariophyta, Chlorophyta, fungi, bacteria, etc. We analyzed the feeding selectivity of R. esculentum by the Ivlev selection index and found that they preferred small- and medium-sized zooplankton like Mollusc and Arthropod. Our results showed that DNA metabarcoding technology has the potential to investigate the feeding habits of jellyfish species.
    Effects of seed carrier-immobilized microorganisms on the growth of rapeseed and the remediation of petroleum hydrocarbon contaminated soil
    ZHOU Yanqiu, LI Fayun, WANG Wei, ZHOU Chunliang, JIANG Rongju
    2024, 35(10):  2897-2906.  doi:10.13287/j.1001-9332.202410.031
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    Petroleum hydrocarbon pollutants in soil are challenging to biodegrade, negatively impacting plant growth as well as the metabolic activity and community structure of soil microorganisms. Microorganisms immobilized by seed carriers can synergistically contribute to the remediation of petroleum hydrocarbon-contaminated soil. We prepared a rape seed carrier with immobilized microorganism by seed coating (with a mixture of diatomaceous earth and bentonite as fillers) and microbial immobilization. A pot experiment was conducted with the following treatments: control (CK, neither seeds nor microorganisms added), bare rapeseed (T1), rapeseed coated with diatomaceous earth and bentonite (T2), free-living Pseudomonas aeruginosa added (T3), rapeseed coated with diatomaceous earth and bentonite plus free-living P. aeruginosa (T4), and rapeseed coated with diatomaceous earth and bentonite immobilized with P. aeruginosa (T5). We measured rape seed growth, rhizosphere microbial community structure, and petroleum hydrocarbon removal efficiency. The results showed that 1) There were no significant difference in seed germination rate among T1, T2, T4, and T5 treatments. Compared to T1, leaf length, root length, biomass, and soluble protein content of rape seed significantly increased in T4 and T5 treatments, while T2 treatment showed no significant effect. Leaf width, stem length, chlorophyll content, and superoxide dismutase activity of rape seed in T2, T4, and T5 treatments were significantly higher than T1, while malondialdehyde content was signi-ficantly lower. 2) Compared to CK, the removal rate of petroleum hydrocarbon in the T1, T2, T3, T4, and T5 treatments increased by 0.8, 1.6, 0.5, 1.8, and 2.2 times, respectively. The T5 treatment achieved the highest petro-leum hydrocarbon removal rate of 54.0%. Soil dehydrogenase activity in all treatments increased significantly, with a positive correlation with the petroleum hydrocarbon removal rate (r=0.893). 3) The T5 treatment had the highest soil microbial α diversity and the abundances of Chloroflexi and Acidobacteria. In conclusion, seed carriers with immobilized microorganisms could regulate plant growth, modify the structures of microbial communities, enhance the biological activity of soil enzymes, thereby improving petroleum hydrocarbon removal efficiency. This provides a novel environmentally friendly approach for the joint remediation of petroleum hydrocarbon-polluted soil by plants and microorganisms.
    Wild boar resource and its conflict with human in Zhejiang Province, East China
    TAN Liping, LIU Junchen, WANG Jianwu, SONG Xiao, ZHANG Shusheng, CHEN Feng, ZHAO Shanshan, XU Aichun
    2024, 35(10):  2907-2915.  doi:10.13287/j.1001-9332.202410.029
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    Human-wildlife conflict is one of the important research topics in biodiversity and conservation. Understanding the status of wildlife resources and its conflict with human could promote the sustainable protection and management of wildlife. Wild boar (Sus scrofa) is one of the most widely distributed ungulates in the world, with an increasing population and recently rising levels of conflict with human. Research on wild boar abundance, distribution and crop damage is an urgent priority in Zhejiang Province, China. We set up a total of 1271 infrared cameras in 11 districts/counties of Zhejiang Province from January 2019 to August 2023 and surveyed the levels of wild boar damage in 90 districts/counties. Results showed that: 1) a total of 5226 independent photos of wild boar were obtained. Based on the random encounter model, the density and number of wild boars in Zhejiang Province was (1.8±0.4) ind·km-2 and (115156±24072) individuals, respectively. 2) Wild boar damage occurred in 60.0% of the districts/counties in Zhejiang Province. The three cities that most seriously damaged by wild boar were Lishui, Hangzhou and Jinhua. 3) The number of conflicts between human and wild boar was positively correlated with vegetation area and negatively correlated with GDP. The area of vegetation damaged by wild boar was positively correlated with the total area of regional vegetation. We found that wild boars are distributed in 11 prefecture-level cities in Zhejiang Province and the population is large. The damage of wild boars and conflicts with people are particularly serious in the mountainous areas in south and west. The damage of wild boars is strongly correlated with vegetation area and GDP.
    Reviews
    Research progress on the effect of estuary microplastics on antibiotic resistance genes
    WANG Qing, QIU Jinghao, SUN Yan, NI Ni, SUN Shaojing, LI Xuli, YANG Shengjuan, LIU Yiran, CUI Yingying
    2024, 35(10):  2916-2924.  doi:10.13287/j.1001-9332.202410.028
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    Estuaries are transitional zones between rivers and marine environments, with intensive human activities. Pollutants pose a threat to the ecological systems of estuaries. Among these pollutants, microplastics and antibiotic resistant genes have gained significant attention due to their potential impacts on estuarine organisms and human health. Microplastics can form unique biofilms, adsorb pollutants from the surrounding environment, and provide potential hosts for antibiotic resistant genes, with positive consequence on horizontal gene transfer of antibiotic resistance. We provided an overview of the pollution status of microplastics and antibiotic resistant genes in estua-rine areas, with a particular emphasis on the influence of biofilms formed on microplastics on the enrichment, transport, and transfer of antibiotic resistant genes. We also highlighted the limitations in current research, regarding microplastic sampling, analysis methods, and inconsistent reporting units. Furthermore, we proposed prospects for the biodegradation of microplastics and potential risk assessment of microplastic biofilms.
    Research progress on quantitative evaluation methods of urban ecological carrying capacity
    ZHAN Mingsong, WANG Mengyuan, LIU Cong, CHU Yaqi, LI Chunlin
    2024, 35(10):  2925-2932.  doi:10.13287/j.1001-9332.202409.022
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    Quantitative evaluation of urban ecological carrying capacity is a critical foundation for measuring urban sustainable development in the new era. This review would enrich the concept and connotation of urban ecological carrying capacity by sorting out its components and characteristics. We categorized the methods for quantifying urban ecological carrying capacity into static evaluation methods, including ecological footprint method, comprehensive evaluation method, state space method, net primary productivity method, and carbon-oxygen balance method, as well as dynamic simulation prediction methods, including system dynamics models, BP neural network prediction models, and grey prediction models. We further summarized both the advantages and disadvantages of these quantitative evaluation methods. Finally, we predicted the development trends of quantitative evaluation methods for urban ecological carrying capacity, and put forward further in-depth research from aspects such as strengthening theoretical foundations, constructing indicator systems, establishing evaluation principles, and optimizing methods.